I. Field
The present disclosure relates generally to electronics, and more specifically to a polyphase filter.
II. Background
A polyphase filter is a circuit that receives one or more input signals having different phases and provides an equal or higher number of output signals having different phases. Polyphase filters may be used for various applications such as quadrature signal generation, image rejection, etc. For quadrature signal generation, a polyphase filter may generate output signals that are in quadrature (or 90° out of phase) of each other.
A polyphase filter may be implemented with capacitors and resistors and may be referred to as an RC polyphase filter. The RC polyphase filter may be implemented on an integrated circuit (IC). The capacitors and resistors may then be fabricated on chip and may benefit from high density, good matching, and high yield. At frequencies of a few gigahertz (GHz) or lower, the capacitors and resistors may have capacitive and resistive behavior, and the RC polyphase filter may provide the desired performance. However, at high frequencies (e.g., tens of GHz), the integrated capacitors may demonstrate inductive behavior, which may result in an ineffective RC polyphase filter.